Selective Oxidation Of Betulin For The Preparation Of Betulinic Acid

Betulinic acid is a pentacyclic terpenoid, and it has remarkably higher anti-tumor and ananti-HIV (Human Immunodeficiency Virus) activity, but the presence of betulinic acid innature is much limited both in terms of content and availability. People always synthesis ofbetulinic acid from betulin, but the old ways all need complex step, long reaction time andhardly reaction temperature. In this paper a selective oxidation for synthesis of betulinic acidfrom betulin has been developed. This system was applied to selectively oxide of the primaryalcohol function of betulin without affecting the secondary hydroxyl group. Betulinic acid canbe synthesized from betulin in only one step.In this paper we first dicide analysis method.We use TLC for qualitative analysis, thecondition is use chlorofrom-methanol20∶1(v/v) as mobile phase,and20%phosphotungsticacid ethanol solution as visualization reagent. The coloration temperature is100-120℃.HPLC for quantitative analysis: The chromatographic separation of the compounds wasachieved by means of a250mm×4.5mm i.d.,5μm particle size, Tigerkin C18column. Themobile phase was methanol-water-acetate85∶15∶0.5%(v/v) at a flow rate of0.8ml/min,peaks were detected at210nm,detected sensitivity is0.005AUFS.This paper also had considered all effect of various experimental conditions such asoxidant, catalyst, reaction solution, reaction time and temperature. The best reaction can becarried out in butyl acetate at25℃using1,3-Dibromo-5,5-dimethylh-ydantoin(DBDMH)inthe presence of catalyst TEMPO for1h. The yield of betulinic acid from betulin was72.1%.